A couple of people have benchmarked constant arrays in this thread, but they've both made the same mistake: not checking what their code is doing and thus drawing bad conclusions.

The problem is that this use constant ARRAY => qw(Title Section Subsection Class Category Degree Attempt CountOfCounts);; does not create an array.

It creates a subroutine which returns an array as a list; which accounts for the inefficiency.

On the other hand: This use constant ARRAY => [ qw(Title Section Subsection Class Category Degree Attempt CountOfCounts) ];; creates a subroutine that return a reference to the array, which you can then index efficiently (especially if you use enum for the indexes):

use constant ARRAY => [ qw(Title Section Subsection Class Category Deg
+ree Attempt CountOfCounts) ];;
use enum = qw(Title Section Subsection Class Category Degree Attempt C
+ountOfCounts);;
@array = qw(Title Section Subsection Class Category Degree Attempt Cou
+ntOfCounts);;

cmpthese -1, {
    var => q[ 
        for(1..1e6){ 
            my $l = $array[ $category ]; 
        } 
    ],
    const => q[ 
        for(1..1e6){ 
           my $l = ARRAY->[ $category ]; 
        } 
    ],
    constenum => q[ 
        for(1..1e6){ 
            my $l = ARRAY->[ Category ]; 
        } 
    ],
};;
            Rate       var     const constenum
var       4.57/s        --       -1%      -18%
const     4.64/s        1%        --      -17%
constenum 5.57/s       22%       20%        --
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